Abstract:To explore the difference in composition and content of free amino acid（FAA）and comprehensive quality of late ripe peaches from Shandong Province，the types and content of FAA in seven kinds of late ripe peaches were determined by liquid phase chromatography-tandem mass spectrometry.Principal component analysis（PCA）was used to comprehensively evaluate FAA in late ripe peaches.The results showed that there were many kinds of FAAs in late ripe peaches，with 20 kinds of FAA detected.The total amount of FAA ranged from 165.169 μg/g to 460.328 μg/g，among which the content of non-essential amino acids was the highest，followed by essential amino acids，and the lowest content was amino acids essential for children.There was no difference in FAA types among different varieties of late ripe peaches，but a significant difference was observed in in FAA content.The contents of flavorful amino acids in late ripe peaches in descending order were umami amino acids＞bitter amino acids＞sweet amino acids＞aromatic amino acids.The correlation analysis showed that there was a significant correlation between different varieties of peaches.Three principal components were extracted from PCA，and the cumulative variance contribution rate was 89.55%.The PCA scores in descending order were Qingqing＞Ruipan101＞Golden Brittle＞Century Peach King＞Qingzhou Honey＞Yingshuang Hong＞Jinqiu Red Honey.FAA component characteristics of some late ripe peaches were significantly different，and PCA could better reflect the comprehensive value of each variety.